diff --git a/ospec/change-log.md b/ospec/change-log.md
index fd133ffb..01ca6f53 100644
--- a/ospec/change-log.md
+++ b/ospec/change-log.md
@@ -3,9 +3,6 @@
 
 ## Upcoming...
 _2019-xx-yy_
-
-## 3.1.0
-_2019-02-05_
 - ospec: Test results now include `.message` and `.context` regardless of whether the test passed or failed. (#2227 @robertakarobin)
 <!-- Add new lines here. Version number will be decided later -->
 - Add `spy.calls` array property to get the `this` and `arguments` values for any arbitrary call. (#2221 @isiahmeadows)
diff --git a/ospec/ospec.mjs b/ospec/ospec.mjs
index e6ea506d..115e0289 100644
--- a/ospec/ospec.mjs
+++ b/ospec/ospec.mjs
@@ -5,6 +5,9 @@ export default (function init(name) {
 	var currentTestError = null
 	if (name != null) spec[name] = ctx = {}
 
+	try {throw new Error} catch (e) {
+		var ospecFileName = e.stack && (/[\/\\](.*?):\d+:\d+/).test(e.stack) ? e.stack.match(/[\/\\](.*?):\d+:\d+/)[1] : null
+	}
 	function o(subject, predicate) {
 		if (predicate === undefined) {
 			if (!isRunning()) throw new Error("Assertions should not occur outside test definitions")
@@ -45,6 +48,7 @@ export default (function init(name) {
 		var spy = function() {
 			spy.this = this
 			spy.args = [].slice.call(arguments)
+			spy.calls.push({this: this, args: spy.args})
 			spy.callCount++
 
 			if (fn) return fn.apply(this, arguments)
@@ -55,6 +59,7 @@ export default (function init(name) {
 				name: {value: fn.name}
 			})
 		spy.args = []
+		spy.calls = []
 		spy.callCount = 0
 		return spy
 	}
@@ -211,6 +216,8 @@ export default (function init(name) {
 	define("notEquals", "should not equal", function(a, b) {return a !== b})
 	define("deepEquals", "should deep equal", deepEqual)
 	define("notDeepEquals", "should not deep equal", function(a, b) {return !deepEqual(a, b)})
+	define("throws", "should throw a", throws)
+	define("notThrows", "should not throw a", function(a, b) {return !throws(a, b)})
 
 	function isArguments(a) {
 		if ("callee" in a) {
@@ -251,6 +258,18 @@ export default (function init(name) {
 		}
 		return false
 	}
+	function throws(a, b){
+		try{
+			a()
+		}catch(e){
+			if(typeof b === "string"){
+				return (e.message === b)
+			}else{
+				return (e instanceof b)
+			}
+		}
+		return false
+	}
 
 	function isRunning() {return results != null}
 	function Assert(value) {
@@ -264,16 +283,20 @@ export default (function init(name) {
 	}
 	function define(name, verb, compare) {
 		Assert.prototype[name] = function assert(value) {
-			if (compare(this.value, value)) succeed(this)
-			else fail(this, serialize(this.value) + "\n  " + verb + "\n" + serialize(value))
 			var self = this
-			return function(message) {
-				if (!self.pass) self.message = message + "\n\n" + self.message
-			}
+			var message = serialize(self.value) + "\n  " + verb + "\n" + serialize(value)
+			if (compare(self.value, value)){
+				succeed(self, message)
+				return function(message) {
+					if (!self.pass) self.message = message + "\n\n" + self.message
+				}
+			}else fail(self, message)
 		}
 	}
-	function succeed(assertion) {
+	function succeed(assertion, message) {
 		results[assertion.i].pass = true
+		results[assertion.i].context = subjects.join(" > ")
+		results[assertion.i].message = message
 	}
 	function fail(assertion, message, error) {
 		results[assertion.i].pass = false